As in the case of the planted seeds, the chemical is also dispensed in a metered manner synchronous with the deposit of the seeds in the soil. Metering of the chemical is accomplished generally by a chemical dispenser driven by an endless chain and idler and drive sprocket combination which is rotationally displaced in response to movement of the planter units. It is desirable to be able to disconnect this chemical metering arrangement from the driving means during seeding of crops that do not require chemical, application. The chemical hoppers are also disconnected from the chemical metering arrangement to facilitate emptying and cleaning of the hoppers particularly when the planting operation calls for the use of a new substance. Occasionally, a hopper must be removed from the planter unit for repair or replacement and this too should be accomplished with minimal impact on the planter unit and without tampering with the metering system.
U.S. Pat. No. 4,359,952 to Gesior et al. discloses an arrangement for attaching a granular chemical hopper to a dispenser. Removal of the hopper assembly from the dispenser is accomplished by removing one or two fasteners, which may be klik pins and disengaging a clutch shaft by pulling the pin and moving the shaft laterally outward and reinstalling the pin in the disengaged position. This approach thus makes use of a loose pin which can easily become lost and requires three separate steps involving removal of the pin, axially displacement of the clutch shaft, and re-insertion of the pin following re-alignment of the associated apertures. This approach is cumbersome, subject to misalignment errors, and requires the replacement of lost pins.
The present invention addresses the aforementioned limitations of the prior art by providing a clutch arrangement for a granular chemical dispenser for use in a planter which permits engagement and disengagement of the dispenser with a simple twist of a readily accessible knob in a single operation. The inventive clutch arrangement is integral with the planter and does not require disassembly or removal of any components.
Accordingly, it is an object of the present invention to provide an improved chemical dispenser installation in an agricultural planter.
Another object of the present intention is to facilitate the connecting and disconnecting of a granular chemical dispenser such as for an insecticide or herbicide in a planter.
A further object of the present invention is to provide an improved manually operable clutch which facilitates coupling and decoupling of a chemical dispenser in an agricultural planter.
A still further object of the present invention is to provide an easily manipulated clutch for use with a chemical dispenser in a planter which is integral with the planter, does not employ any loose parts, and requires only a single operation to engage or disengage the dispenser.
This invention contemplates a clutch apparatus for coupling the rotor of a granular chemical dispenser in a planter to a drive mechanism, the apparatus comprising a shaft coupled to the drive mechanism and having gripping means on a first end and a coupler on a second, opposed end thereof; bearing means for rotationally coupling the shaft to a housing, wherein the shaft is moveable along a longitudinal axis thereof within the bearing means; biasing means coupled to the shaft for urging the shaft toward the rotor whereupon the coupler engages the rotor; axial displacement means coupled to the shaft for moving the shaft away from the rotor and for disconnecting the coupler from the rotor when the shaft is rotated in a first direction in decoupling the dispenser from the drive mechanism; and retaining means coupled to the shaft for maintaining the shaft and coupler axially displaced from the rotor, whereupon rotation of the shaft in a second, opposed direction causes displacement of the shaft toward and engagement of the coupler with the rotor under the influence of the biasing means.